1. Field of the Invention
This invention relates to a highly integrated semiconductor device, and more particularly, to a contact of semiconductor device used to improve the integrity of the semiconductor device by minimizing the line width of an upper conducting line that forms on the contact area and prevent damages on a lower conducting line when the upper conducting line makes contact with the lower conducting line.
2. Background of the Invention
During the semiconductor fabricating process, a conducting line is formed on a semiconductor substrate and an insulating layer is formed over the conducting line. And then the conducting line makes contact with another conducting line overlying the insulating layer. In general, after the formation of the lower conducting line and the insulating layer overlying the lower conductive line, a contact hole is made at a selected area to expose a portion of the lower conducting line and a conducting material is filled in the contact hole. Thereafter, a conducting layer is formed on the insulating layer and on the contact hole, and patterned to make an upper conducting line.
However, the patterning of the upper conducting line should be performed in such a way that the upper conducting line completely becomes overlaps with an upper surface of the contact hole or a contact area. If the upper conducting line fails to overlap with the contact area, the lower conducting line of the lower part of the contact is damaged during the patterning process, resulting in a defective device. Therefore, the lower and upper conducting lines must be formed by observing a certain design rule. That is, in order to make the upper conducting line contact with the lower conducting line, the upper conducting line must always overlap with the contact area. However, because the registration, CD (Critical Dimension) variation, misalignment tolerance, and the lens distortion must be considered during the patterning and/or masking process, the line width of the upper conducting line should be larger than the size of the contact. As a result, the high integrity of the device is lost.